Pengaruh Penempatan Lightning Arrester Sebelum Dan Sesudah Fuse Cut Out Terhadap Tegangan Lebih Pada Transformator Distribusi 20 Kv Di PT. PLN (Persero) Rayon Tanjung Karang

Abstract

Lightning strikes on airborne transmission networks such as in distribution lines are injections of electric charge. The injection of the charge will cause a voltage increase in the network, so that more tension will arise in the network. Lightning Arrester (LA) is one of the equipment in the protection system to protect the 20 kV distribution transformer against overvoltage coming from lightning strikes. Under normal circumstances LA acts as an insulator, but when exposed to lightning strikes LA will function as a conductor whose resistance is relatively low, so that it can flow the surge current to the ground. This study aims to see the effect of the placement of lightning arresters before and after fuse cut out on overvoltage in the 20 KV distribution transformer, so that which placement is better is obtained, taking into account factors that affect the level of voltage and overcurrent that occurs in each system such as the location of LA placement, the steepness of incoming waves, the speed of propagation of surja waves, the voltage is large through the protection system, and the Basic Insulation Level (BIL) value of the equipment. So that in the end, the right PLACEMENT of LA was obtained as a 20 kv distribution transformer protection. Based on the results of the study, the voltage that reached the transformer was 67,192 kV, in this condition the transformer was still in a safe state because the voltage hitting the transformer was smaller than the transformer's BIL, which was 67.192kV<125 kV. the installation of the arrester after Fuse Cut Out is better because the voltage hitting the transformer is smaller than the installation of the arrester before Fuse Cut Out with a voltage difference of 69,092 kV - 67,192 kV = 1.9 kV.